Bangalore city was put on high alert following the attack on the IISc.In a suspected terrorist attack, unidentified gunmen today barged into the premier Indian Institute of Sciences (IISc) during an international conference and opened fire killing a retired professor of Indian Institute of Technology, Delhi, and wounding four others.The police identified the deceased as M C Puri, professor Emeritus in mathematics department of Delhi IIT. He retired two to three years ago. The injured were Dr Pankaj Gupta, Dr Sangeeta, Dr Vijay Chandru and Dr Vijay Patil.An AK-47 rifle, three magazines of an automatic weapon and a hand grenade were recovered from the scene of firing, police sources said.Sources said the possibility of terror attack could not be ruled out given the nature of the automatic weapons used in the attack and the recovery of the grenade. The institute is on the hit list of terror groups including Pakistan-based Lashkar-e-Taiba.However, Bangalore police commissioner Ajay Kumar Singh, when asked if this was a terrorist strike, said "we cannot say anything at this stage.""There is no information on how they came and who they were", he said.Union home secretary Vinod Kumar Duggal said in New Delhi that "as of now it is not a terrorist attack."